Backpacking

input/backpack.scala:1: error: expected class or object definition
var A = 5
^
input/backpack.scala:2: error: expected class or object definition
var B = 3
^
input/backpack.scala:3: error: expected class or object definition
var O = A + B
^
input/backpack.scala:4: error: expected class or object definition
O
^
four errors found

var A = 5
var B = 3
var O = A + B
O